scholarly journals Ecology of Diaporthe eres, the causal agent of hazelnut defects

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247563
Author(s):  
Roberta Arciuolo ◽  
Marco Camardo Leggieri ◽  
Giorgio Chiusa ◽  
Giuseppe Castello ◽  
Giuseppe Genova ◽  
...  
Keyword(s):  
Incubation Period ◽  
Biological Process ◽  
Abiotic Factors ◽  
Crop Protection ◽  
Fungal Growth ◽  
Visual Observation ◽  
Causal Agent ◽  
Protection Strategy ◽  
Asexual Spore ◽  
Regression Functions

Diaporthe eres has been recently reported as the causal agent of hazelnut defects, with characteristic brown spots on the kernels surface and internal fruit discoloration. Knowledge regarding the ecology of this fungus is poor but, is critical to support a rationale and effective hazelnut crop protection strategy. Therefore, a study was performed to describe and model the effect of different abiotic factors such as temperature (T, 5–35°C, step 5°C) and water activity (aw 0.83–0.99, step 0.03) regimes on D. eres mycelial growth, pycnidial conidiomata development and asexual spore production during a 60-day incubation period. Alpha conidia germination was tested in the same T range and at different relative humidities (RH = 94, 97 and 100%) over 48 h incubation period. Fungal growth was observed from the first visual observation; regarding pycnidia and cirrhi, their development started after 8 and 19 days of incubation, respectively and increased over time. The optimum T for growth was 20–25°C and for pycnidia and cirrhi development was 30°C; aw ≥ 0.98 was optimal for the tested steps of the fungal cycle. The best condition for conidial germination of D. eres was at 25°C with RH = 100%. Quantitative data obtained were fitted using non- linear regression functions (Bete, logistic and polynomial), which provided a very good fit of the biological process (R2 = 0.793–0.987). These functions could be the basis for the development of a predictive model for the infection of D. eres of hazelnuts.

scholarly journals Isolation and efficacy of two bacterial strains antagonists of Erwinia amylovora and Pectobacterium carotovorum

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
M’hamed BENADA ◽  
Boualem BOUMAAZA ◽  
Sofiane BOUDALIA ◽  
Omar KHALADI
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Species ◽  
Crop Protection ◽  
Soft Rot ◽  
Causal Agent ◽  
Plant Diseases ◽  
Ecological Niches ◽  
Pectobacterium Carotovorum ◽  
Bacterial Strains

Abstract Background The development of ecofriendly tools against plant diseases is an important issue in crop protection. Screening and selection process of bacterial strains antagonists of 2 pathogenic bacterial species that limit very important crops, Erwinia amylovora, the causal agent of the fire blight disease, and Pectobacterium carotovorum, the causal agent of bacterial potato soft rot, were reported. Bacterial colonies were isolated from different ecological niches, where both pathogens were found: rhizosphere of potato tubers and fruits and leaves of pear trees from the northwest region of Algeria. Direct and indirect confrontation tests against strains of E. amylovora and P. carotovorum were performed. Results Results showed a significant antagonistic activity against both phytopathogenic species, using direct confrontation method and supernatants of cultures (p<0.005). In vitro assays showed growth inhibitions of both phytopathogenic species. Furthermore, results revealed that the strains of S. plymuthica had a better inhibitory effect than the strains of P. fluorescens against both pathogens. In vivo results on immature pear fruits showed a significant decrease in the progression of the fire blight symptoms, with a variation in the infection index from one antagonistic strain to another between 31.3 and 50%, and slice of potato showed total inhibition of the pathogen (P. carotovorum) by the antagonistic strains of Serratia plymuthica (p<0.005). Conclusion This study highlighted that the effective bacteria did not show any infection signs towards plant tissue, and considered as a potential strategy to limit the fire blight and soft rot diseases.

scholarly journals Some aspects of alder decline along the Lužnice River

2012 ◽  
Vol 51 (No. 9) ◽  
pp. 381-391 ◽  
Author(s):  
I. Vyhlídková ◽  
D. Palovčíková ◽  
M. Rybníček ◽  
P. Čermák ◽  
L. Jankovský
Keyword(s):  
Czech Republic ◽  
Tree Ring ◽  
Fungal Pathogen ◽  
Abiotic Factors ◽  
Health Condition ◽  
Causal Agent ◽  
Direct Effects ◽  
Biotic Factor ◽  
The Czech Republic ◽  
Secondary Activation

Alder decline along watercourses is one of the marked manifestations of tree decline in the Czech Republic. Local decline of alder trees is documented in the Czech Republic for about 15 years. The aim of this paper is to evaluate causes of alder decline and assess health conditions of other species of riparian stands at 2 localities on the medium reach of the Lužnice River. Effects were studied of abiotic and biotic stressors on the health condition of tree species. No fungal pathogen was found in tissues of declining alders which would be present in all trees and which could be considered to be the main causal agent of the decline. Even an occurrence of the causal agent of alder decline named alder-Phytophthora has not been proved. Tree-ring analyses demonstrated decreasing trends of an increment in alders; however, an abiotic or biotic factor showing direct effects on the fluctuation of tree ring dimensions has not been positively determined. A marked role in the alder decline is demonstrated particularly by abiotic factors accompanied by the secondary activation of some pathogens. Generally, the phenomenon can be named as polyetiologic decline.

scholarly journals Effects of waterlogging stress on plant-pathogen interaction between Fusarium poae and wheat/ barley

2019 ◽  
Vol 41 (1) ◽  
pp. 42629 ◽  
Author(s):  
Mauro Martinez ◽  
Agustín Francisco Arata ◽  
Laura Lázaro ◽  
Sebastian Alberto Stenglein ◽  
María Inés Dinolfo
Keyword(s):  
Yield Components ◽  
Grain Quality ◽  
Abiotic Factors ◽  
Fusarium Species ◽  
Fungal Growth ◽  
Waterlogging Stress ◽  
Fusarium Poae ◽  
Waterlogging Treatment ◽  
Favorable Conditions

Waterlogging stress is one of the abiotic factors which causes damage to crops affecting yield components and grain quality of wheat and barley. On the other hand, Fusarium poae is one of the most common Fusarium species isolated from wheat and barley. The aim of this study was to evaluate the effects of waterlogging and F. poae on disease parameters, yield components and grain quality of durum and bread wheat and barley. The experiment was carried out using pots under greenhouse conditions. Four treatments were applied: control/control (W0F0), control/F. poae (W0F1), waterlogging/control (W1F0) and waterlogging/F. poae (W1F1). The results showed that incidence, severity and FHB index of F. poae were higher in W0F1 compared to W1F1 suggesting that waterlogging treatment would be generating no favorable conditions for fungal growth. Therefore, yield components and grain composition and quality were significantly affected by the Fusarium presence and waterlogging treatment which could induce changes in parameters mainly related to the industrial quality of wheat and barley. These results highlight the behavior of wheat and barley under the combination of abiotic and biotic stress.

scholarly journals Biological Control of Thielaviopsis paradoxa and Colletotrichum gloeosporioides by the Extracellular Enzymes of Wickerhamomyces anomalus

Agriculture ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 325
Author(s):  
Luis Fernando Zepeda-Giraud ◽  
Dario Rafael Olicón-Hernández ◽  
Juan Pablo Pardo ◽  
Minerva Georgina Araiza Villanueva ◽  
Guadalupe Guerra-Sánchez
Keyword(s):  
Extracellular Enzymes ◽  
Colletotrichum Gloeosporioides ◽  
Culture Media ◽  
Crop Protection ◽  
Fungal Growth ◽  
Antagonistic Effect ◽  
Economic Losses ◽  
Post Harvest ◽  
Wickerhamomyces Anomalus ◽  
Yeast Peptone Dextrose

An alternative to chemical fungicides in post-harvest diseases are the use of biocontrol agents and their extracellular products against phytopathogens. Two relevant agents in post-harvest infections are Thielaviopsis paradoxa and Colletotrichum gloeosporioides, causing large economic losses in cacao, pineapple, and avocado during storage. In this work, we evaluated the effect of Wickerhamomyces anomalus, an effective biocontrol agent, against these filamentous fungi, focusing on the production of extracellular enzymes and their effect on fungal growth and germination. Moreover, we evaluated the use of inactivated fungal biomass as an inducer in complete (Potato Dextrose Agar and Yeast Peptone Dextrose) and minimal culture media. The antagonistic effect of W anomalus on the growth of both phytopathogens was also studied. The extracellular enzymes in YPD cultures, using T. paradoxa inactivated biomass as the best inducer, were capable of inhibiting the germination of both phytopathogens. In minimal media, only the production of a 30 kDa glucanase with activity against laminarin was observed. The enzyme was effective against the spore germination of T. paradoxa. In post-harvest crop protection tests, growth inhibition of T. paradoxa was observed using the cell-free enzyme extract, which is a promising system to protect cocoa fruits from T. paradoxa during post-harvest.

scholarly journals Botrytis squamosa - the causal agent of onion leaf blight in Bosnia and Herzegovina

2019 ◽  
Vol 34 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Brankica Tanovic ◽  
Milan Koscica ◽  
Jovana Hrustic ◽  
Milica Mihajlovic ◽  
Vojislav Trkulja ◽  
...  
Keyword(s):  
Bosnia And Herzegovina ◽  
Internal Transcribed Spacer ◽  
Abiotic Factors ◽  
Its Region ◽  
Causal Agent ◽  
Botrytis Squamosa ◽  
The Past ◽  
Leaf Spots ◽  
Necrotic Spots ◽  
Temperature And Growth

Over the past several decades, necrotic spots, lesions and blight symptoms have been observed on onion leaves in several locations in Bosnia and Herzegovina, where the crop is grown intensively. The type of symptoms indicated a possible infection with Botrytis squamosa, a widespread pathogen of onion. As symptoms of leaf spots and necrotic lesions can also be caused by some other biotic and abiotic factors, our research focused on identifying the causal agent of the observed symptoms. The pathogen was isolated from diseased tissue using standard phytopathological procedure and identified based on pathogenic and morphological features. Identification was confirmed by amplification and sequencing of the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA). The influence of temperature and growth medium on mycelial growth rate of the isolates was also studied.

scholarly journals Evaluation of Chestnut Susceptibility to Cryphonectria parasitica: Screening under Controlled Conditions

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1158
Author(s):  
Emigdio Jordán Muñoz-Adalia ◽  
Andreu Meijer ◽  
Joan Abel ◽  
Carlos Colinas ◽  
Neus Aletà ◽  
...  
Keyword(s):  
Fungal Growth ◽  
Longitudinal Axis ◽  
Cryphonectria Parasitica ◽  
Causal Agent ◽  
Chestnut Blight ◽  
Vascular Tissues ◽  
Individual Genotype ◽  
Controlled Conditions ◽  
The Individual ◽  
Preliminary Selection

Cryphonectria parasitica (Murrill) M.E. Barr (Sordariomycetes, Valsaceae) is the causal agent of chestnut blight. This disease is a major concern for chestnut cultivation in Europe. The fungus colonizes vascular tissues and evolves generating cankers causing severe dieback and the death of the tree. Excised and debarked well-lignified shoots of 28 C. sativa genotypes (assay A) and of 10 progenies (assay B) were inoculated with C. parasitica strain FMT3bc2 (vcg: EU2). Fungal growth was measured along the longitudinal axis on the 3rd and 6th days after inoculation. Results indicated the inoculation methodology works and the results were clear after 6 days. Differences in susceptibility to chestnut blight among C. sativa trees of Montseny have been detected both at the individual genotype level and at the progeny level. Nineteen genotypes and four progenies showed a susceptibility to Blight not significantly different from C. mollissima. The methodology was easy to apply in extensive/preliminary selection screenings to assess the susceptibility of C. sativa materials to the Blight.

scholarly journals RICE PLANT DISEASE CLASSIFICATION USING TRANSFER LEARNING OF DEEP CONVOLUTION NEURAL NETWORK

2019 ◽  
Vol XLII-3/W6 ◽  
pp. 631-635 ◽  
Author(s):  
V. K. Shrivastava ◽  
M. K. Pradhan ◽  
S. Minz ◽  
M. P. Thakur
Keyword(s):  
Neural Network ◽  
Rice Plant ◽  
Plant Disease ◽  
Crop Protection ◽  
Visual Observation ◽  
Plant Diseases ◽  
Disease Classification ◽  
Real Field ◽  
Support Vector ◽  
Identification System

<p><strong>Abstract.</strong> Early and accurate diagnosis of plant diseases is a vital step in the crop protection system. In traditional practices, identification is performed either by visual observation or by testing in laboratory. The visual observation requires expertise and it may vary subject to an individual which may lead to an error while the laboratory test is time consuming and may not be able to provide the results in time. To overcome these issues, image based machine learning approach to detect and classify plant diseases has been presented in literature. We have focused specifically on rice plant (<i>Oryza sativa</i>) disease in this paper. The images of the diseased symptoms in leaves and stems have been captured from the rice field. We have collected a total of 619 rice plant diseased images from the real field condition belong to four classes:(a) Rice Blast (RB), (b) Bacterial Leaf Blight (BLB), (c) Sheat Blight (SB) and (d) Healthy Leave (HL). We have used a pre-trained deep convolutional neural network(CNN) as a feature extractor and Support Vector Machine (SVM) as a classifier. We have obtained encouraging results. The early identification of rice diseases by this approach could be used as a preventive measure well as an early warning system. Further, it could be extended to develop a rice plant disease identification system on real agriculture field.</p>

scholarly journals Effect of Abiotic Factors on the Antifungal Activity of Lactobacillus Strains Isolated from Commercial Dairy and Fermented Foods from Federal Capital Territory, Nigeria

2021 ◽  
pp. 70-78
Author(s):  
Mercy Aboh ◽  
Ngozi Amaeze ◽  
Ijeoma Ikeji ◽  
Peters Oladosu
Keyword(s):  
Lactic Acid ◽  
Antifungal Activity ◽  
Lactic Acid Bacteria ◽  
Aspergillus Fumigatus ◽  
Inhibitory Activity ◽  
Abiotic Factors ◽  
Fungal Growth ◽  
Effective Alternative ◽  
Dual Culture ◽  
Antifungal Compounds

Increasing consumer demand for natural products have renewed food industry attention in bio preservation. Lactic acid bacteria are of particular interest as effective alternative to chemical preservation because of their food grade status. This work explores the effect of antifungal compounds produced by isolates of Lactobacillus sp on some selected pathogenic fungi growth. Samples of diary and fermented products were purchased from commercial vendors within the Federal Capital Territory (FCT) and screened for the presence of Lactobacillus sp. The Lactobacillus sp isolated were screened for antifungal activity against Aspergillus fumigatus, Candida albicans and Trichophyton rubrum using a dual culture assay. Strains with antifungal activity were identified and the fungal inhibitory activity was further evaluated. The effect of abiotic factors on the antifungal activity was evaluated by overlay assay under different temperature and pH. Majority of the identified isolates belonged to the genus Lactobacillus. Lactobacillus sp. produced antifungal compounds under different temperatures (25ºC, 30ºC and 37ºC). The antifungal compounds produced by Lactobacillus strains showed greater inhibitory activity on Aspergillus fumigatus. At 30ºC the percentage zones of inhibition range were 44.4%- 60.4%. All isolates showed stronger antifungal activity when grown at pH 4.0 and 5.0. At a pH 2.0 there was a total inhibition of fungal growth however, there was no inhibition of fungal growth at the pH 7.0. Lactic acid bacteria can be employed as effective alternative to chemical preservatives in food. Temperature and pH of the culture medium could influence the production of antifungal compounds by lactic acid bacteria.

scholarly journals NPR1 as a transgenic crop protection strategy in horticultural species

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Katchen Julliany P. Silva ◽  
Nasser Mahna ◽  
Zhonglin Mou ◽  
Kevin M. Folta
Keyword(s):  
Crop Protection ◽  
Transgenic Crop ◽  
Protection Strategy
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